Somatic Cell
Gene Therapy and Germ Line Gene Therapy

There
are two basic "classes" of gene therapy. Somatic cell
gene therapy and germ line gene therapy.

· Somatic
cell gene therapy changes/fixes/replaces genes in just one person.
The targeted cells are the only ones affected, the changes are not
passed on to that person's offspring.

· Germ
line gene therapy makes changes in the sperm or egg of an individual.
The changes that are made, adding or subtracting genes from the
person's DNA, will be passed on to their offspring. This type of
gene therapy raises a lot of ethical questions because it impacts
the inheritance patterns of humans.

For more information,
listen to Dr. Charles Link in Viewpoints.

Gene therapy
can be accomplished "ex-vivo" or "in-vivo."
Ex-vivo means the target cells are removed from the patient's body,
the genes are fixed or replaced, and the cells are put back into
the person. In-vivo means the genes are "injected" somehow,
usually using a virus as a way to deliver the fixed or missing genes.